package exam.ant.S1;

import java.util.*;

public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        System.out.println(solution(n));
    }

    private static String solution(int n) {
        int[] cnt = new int[26];
        cnt[0] = 1;
        for (int i = 1; i < 26; i++)
            cnt[i] = 2 * cnt[i-1];
        int i = 25;
        StringBuilder sb = new StringBuilder();
        while (n > 0) {
            if (n >= cnt[i]) {
                int k = n / cnt[i];
                n %= cnt[i];
                for (int j = 0; j < k; j++)
                    sb.append((char) (i + 'a'));
            }
            i--;
        }
        return sb.toString();
    }
}
